Biosorption of copper(II) ions using timber industry waste based biomass

Abstract

The processing and characterization of timber industry waste based saw dust and its biosorption studies towards Cu (II) ions is the focus of the present study. The processing of saw dust involved (i) boiling with water (ii) treatment with formaldehyde and (iii) treatment with sulphuric acid to get three new adsorbents abbreviated as SDB (boiled saw dust), SDF (formaldehyde treated saw dust) and SDS (sulphuric acid treated saw dust), respectively. CHNSO, SEM-EDS, FTIR and BET surface area techniques were used for the characterization of SDB, SDF and SDS. These adsorbents were used for the comparative investigation of Cu (II) ions remediation in a batch process. Effects of procedural variables like pH, contact period, starting concentration of Cu (II) ions, the quantity of adsorbent, temperature and agitation speed were investigated for the removal of metal ions under study on SDB, SDF and SDS adsorbents. Isothermal studies were carried out using Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. From Langmuir isotherm, the maximum adsorption capacity was calculated as 98.81, 178.57 and 142.85 mg/g for SDB, SDF and SDS adsorbents, respectively. Kinetic studies indicate that the rate of Cu (II) ions adsorption follows pseudo-second-order kinetics. Studies of free energy changes suggest the process of biosorption as spontaneous and feasible. Enthalpy change values indicate the process of adsorption to be exothermic for SDB, SDF and endothermic for SDS. The results of desorption studies revealed that biosorbents used in present work are promising biosorbents for remediating copper from aqueous solution.